KR101048390B1 - Target track search method of optical disk device - Google Patents

Abstract

The present invention relates to a method for rapidly searching a target track on an optical disc, wherein the track pitch value for a large capacity disc and the number of tracks per step are detected and stored during the target track search on the optical disc. Calculating a number of moving tracks to the target track with reference to a pitch value and moving the optical pickup accordingly; In the first step, when the optical pickup does not move accurately to the target track, determining whether or not the track pitch or the number of tracks per one step has been detected beforehand; And a third step of correcting the track pitch or the number of tracks per one step previously detected and stored according to the determination result, and then moving the optical pickup to the target track. The number of moving tracks is calculated and shifted by the calculated number of moving tracks on the basis of the track pitch value, and the predetermined track pitch value or the number of moving tracks per one step is corrected from the moving result, thereby making it possible to target a large capacity disc. It is a very useful invention that can search a track at a higher speed.

Fine Search, Rough Search, Track Pitch, Wobble, Correction

Description

Method for searching target track in optical disc device             

1 is a block diagram of an embodiment of an optical disk device in which a target track search method according to the present invention is implemented.

2 and 3 show the flow of a preferred embodiment of the target track search method of the optical disk apparatus according to the present invention.

[Description of Drawings]

M1: Spindle Motor M2: Sled Motor

10: optical disc 20: optical pickup

30: R / F part 40: digital signal processing part

50: servo unit 60: drive unit

70: micom 71: memory

The present invention relates to a target track search method of an optical disk apparatus for quickly and accurately accessing a target position on an optical disk using a value updated through a predetermined learning operation.

In the optical disk drive such as CD-ROM driver, the target track must be searched at high speed for the high speed data access, and the current track (T _rc ) and the target track are required for the target track search. The track difference (ΔT _r = T _rt -T _rc ) between (T _rt ) should be accurately calculated. An example of calculating the track difference (Track Difference) is as follows.

π (r ₁ ² -r ₂ ² ) = p v _{c c} (t ₁ -t ₂ ), r ₁ = r ₀ + p T _rc (where p: Track Pitch, r ₀ : Program start position (= 0.025m), t ₀ : program start position time (= 00:00:00), t ₁ : current position time, v _c : disk linear velocity) (T _rc ) is

(이때, T_rc : r₀ 에서 r₁ 까지의 트랙 수임)과 같이 나타낼 수 있으며,

(Where T _rc : is the number of tracks from r ₀ to r ₁ ),

Since r ₂ = r ₀ + p T _rt , the target track T _rt of the optical pickup is

(이때, T_rt : r₀ 에서 r₂ 까지의 트랙수임)과 같이 나타낼 수 있다.

Where T _{rt is the} number of tracks from r ₀ to r ₂ .

When the current track T _rc and the target track T _rt of the optical pickup are obtained from the above formula, the track difference ΔT _r = T _rt -T _rc , that is, the number of moving tracks can be obtained.

When the number of moving tracks is calculated as described above, a long track jump operation, that is, a rough search operation, is performed to drive an optical pickup to a target track by driving a sled motor for a predetermined time. When the stepping motor is used as the red motor, the number of tracks per step is preset, but this depends on the track pitch value.

For example, assuming that the track pitch value is 1.6 μm and 0.91 μm moves in 1 μ-step, 0.57 tracks are moved per 1 μ-step, so the number of tracks per step is detected and set therefrom.

When the number of moving tracks is calculated as described above, the optical pickup is moved to a target track by driving the stepping motor by a predetermined step with reference to the calculated number of moving tracks and the preset number of tracks per step. The pickup does not move accurately to the target track but rather near the target track, which is based on the track pitch value (1.6 μm) for the standard capacity disc, regardless of the actual track pitch value of the inserted optical disc. This is because the number is calculated.

That is, the track pitch value differs slightly from disc to disc. Especially for an optical disc whose data recording capacity is standard capacity (74 minutes), which differs depending on the recording capacity of the disc, the track pitch value is about 1.6 μm, but the data recording capacity is different. An optical disc of 80 minutes has a smaller value than an optical disc of 74 minutes.

Therefore, when the optical pickup reaches the target track through the rough search operation, the calculated number of moving tracks is compared with the number of actual moving tracks, and the number of tracks per one step set as an initial value is corrected therefrom, or By correcting the set track pitch value, the next track can be closer to the target track.

After reaching the target track, a fine search operation is performed to accurately search the target track by applying jump pulses such as kick pulses and brake pulses to the optical pickup internal actuators. Done.

However, despite the trend that the capacity of optical discs is gradually increasing, conventionally, since the number of tracks for moving optical pickups is calculated using a track pitch value for an optical disc of standard capacity, an optical disc having a capacity larger than the standard capacity is inserted. In this case, even if the calculated number of moving tracks is large, the track difference with the target track is large, so it has to go through several search processes before moving precisely to the target track.

Accordingly, the present invention was created to solve the above problems, and by calculating and moving the number of moving tracks based on the track pitch value of a large capacity optical disk according to the trend of increasing the capacity of optical disks, the target track can be made faster. It is an object of the present invention to provide a target track search method for an optical disk device that can be searched by a user.

In the target track search method of the optical disk apparatus according to the present invention for achieving the above object, when the target track search on the optical disk, the track pitch value and the number of tracks per step for the large capacity disk is already detected and stored, A first step of calculating the number of moving tracks to the target track by referring to the detected and stored track pitch value and moving the optical pickup accordingly; In the first step, when the optical pickup does not move accurately to the target track, determining whether or not the track pitch or the number of tracks per one step has been detected beforehand; And a third step of moving the optical pickup to the target track after correcting the track pitch or track number per step previously detected and stored according to the determination result.

Hereinafter, a preferred embodiment of a target track search method of an optical disk apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 shows the configuration of an embodiment of an optical disk apparatus in which the track pitch correction method according to the present invention is implemented, which includes an optical pickup 20 for reading a recording signal from the optical disk 10; An R / F unit 30 for shaping the signal detected by the optical pickup 20 and outputting it as a binary signal; A digital signal processor (40) for restoring the binary signal to original data with its own clock synchronized with the binary signal; A drive unit (60) for driving a spindle motor (M1) for rotating the optical disc (10) and a sled motor (M2) for moving the optical pickup (20); A servo unit (50) for controlling the drive of the drive unit (60) from the servo error signals (F.E, T.E) output from the optical pickup (20) and the rotational speed of the optical disc (10); A memory 71 in which data such as a track pitch value, the number of moving tracks per step, and a flag value are stored; And a microcomputer 70 that calculates the number of moving tracks with reference to the stored value, moves the calculated number of moving tracks, and corrects the value stored in the memory 71 from the result.

In the above configuration, the memory 71 is preferably composed of a nonvolatile memory.

2 and 3 show the flow of a preferred embodiment of the target track search method of the optical disk apparatus according to the present invention, and the following is a correction method of FIGS. 2 and 3 according to the present invention with reference to the configuration of FIG. It will be described in detail.

First, in the memory 71, a track pitch value (e.g., 1.2 mu m) for a large capacity disk and the number of tracks per step are detected and stored. In addition, 1 is set and stored as a flag value.

As described above, when the track pitch value is 1.2 μm, assuming that 0.91 μm is moved in 1 μ-step, 0.76 tracks are moved in 1 μ-step, so that the number of tracks per step is detected and stored therefrom.

In this state, when the target track is to be searched (S10), first, the microcomputer 70 calculates the current track and the target track according to the above calculation formula and calculates the number of moving tracks (S11). In this case, the current track and the target track are obtained using the track pitch values of the large capacity disks previously stored in the memory 71, not the track pitch values of the standard capacity disks.

The microcomputer 70 calculates how much the sled motor M2, which is composed of a stepping motor, is to be driven from the calculated number of moving tracks and the number of tracks per step of the memory 71 so as to drive the sled motor. By driving the predetermined step M2, the optical pickup 20 is long jumped (rough search) to the target track (S12).

However, if the optical pickup 20 does not accurately move to the target track through the rough search (S20), the microcomputer 70 may move the target track and the current track or the calculated number of moving tracks and the It is determined whether or not the number of tracks or track pitch values per step stored in the memory 71 is corrected from the actual number of moving tracks through the rough search operation (S21). In step S40, the rough search is made in the outer circumferential direction of the optical disk 10 or in the inner circumferential direction.

If the rough search is made in the outer circumferential direction of the optical disc 10, the microcomputer 70 checks whether the optical disc 10 is determined to be a press or wobble disc in a previous initial disc recognition process (S50). This can be determined simply from the characteristics of the medium of the disc.

If the optical disc 10 is found to be a press or wobble disc, the microcomputer 70 corrects the number of tracks per step stored in the memory 71 by one step or decreases the track pitch value stored in the memory 71. If the optical disk 10 is not a press or wobble disk, the microcomputer 70 checks the flag value stored in the memory 71 and the value is 1, (S52) The number of tracks per step stored in the memory 71 is largely corrected (for example, eight steps) or the track pitch value of the memory 71 is significantly corrected (S53).

However, if the checked flag value is not 1, the microcomputer 70 corrects the number of tracks per step stored in the memory 71 by one step or corrects the track pitch value of the memory 71 by one step. (S54).

In the above embodiment, if the rough search is made in the inner circumferential direction of the optical disc 10, the microcomputer 70 corrects the number of tracks per step stored in the memory 71 by one step. The track pitch value of the memory 71 is corrected in one step (S41), and the flag value stored in the memory 71 is reset to zero (S42).                     

As described above, when it is determined that the number of tracks or track pitch values per step stored in the memory 71 is corrected or that correction is not necessary, the microcomputer 70 of the sled motor M2 By stopping the driving and performing a fine search operation while applying a jump pulse such as a kick pulse and a brake pulse to the actuator inside the optical pickup 20, the optical pickup 20 is accurately moved to the target track (S43). In operation S44, a requested operation (for example, a playback operation) is performed from the moved target track.

As described above, according to the present invention, the number of tracks per track or track pitch value initially set in the memory 71 is appropriately corrected, and when the target track is searched again later, the target track is searched at higher speed by the corrected value. You can do it.

The above-described preferred embodiments of the present invention are disclosed for purposes of illustration, and those skilled in the art can improve, change, and substitute various other embodiments within the technical spirit and scope of the present invention disclosed in the appended claims below. Or addition may be possible.

In the target track search method of the optical disk apparatus according to the present invention, the number of moving tracks is calculated and moved by the calculated number of moving tracks based on the track pitch value of the large capacity optical disk according to the trend of increasing the capacity of the optical disk. By correcting the preset track pitch value or the number of moving tracks per step from this freezing, it is a very useful invention that can search the target track at a higher speed in a large capacity disk.

Claims (6)

delete With the track pitch value for a large capacity disc and the number of tracks per step already detected and stored, A first step of calculating the number of tracks to be moved to the target track by referring to the track pitch value detected and stored in the target track search on the optical disc and moving the optical pickup accordingly; In the first step, if the optical pickup does not accurately move to the target track, the optical pickup is moved to the target track after correcting the track pitch or the number of tracks per one step that are detected and stored. If the movement of the first step is an outer circumferential direction of the optical disc and the optical disc is a press or wobble disc, a second step of lowering the track number per track for each step previously detected or correcting the track pitch value to a smaller value is performed. A target track search method for an optical disc device, comprising: With the track pitch value for a large capacity disc and the number of tracks per step already detected and stored, A first step of calculating the number of tracks to be moved to the target track by referring to the track pitch value detected and stored in the target track search on the optical disc and moving the optical pickup accordingly; In the first step, if the optical pickup does not accurately move to the target track, the optical pickup is moved to the target track after correcting the track pitch or the number of tracks per one step that are detected and stored. If the movement of the first step is an outer circumferential direction of the optical disc and the optical disc is not a press or wobble disc, the preset flag value is checked and the flag value is 1. When the flag value is 1, the number of tracks per one step previously detected and stored is greatly reduced. And a second step of correcting or greatly upwardly correcting the track pitch value. The method of claim 3, In the second step, when the flag value is not 1, the target track search method of the optical disk apparatus, characterized in that the track number per one step is detected to be lowered down or the track pitch value is lowered upward. . With the track pitch value for a large capacity disc and the number of tracks per step already detected and stored, A first step of calculating the number of tracks to be moved to the target track by referring to the track pitch value detected and stored in the target track search on the optical disc and moving the optical pickup accordingly; In the first step, if the optical pickup does not accurately move to the target track, the optical pickup is moved to the target track after correcting the track pitch or the number of tracks per one step that are detected and stored. And if the movement of the first step is an inner circumferential direction of the optical disc, a second step of lowering upwardly correcting the number of tracks per one step that have been detected and stored or lowering downwardly the track pitch value. Target track search method of device. The method of claim 5, The second step is a target track search method for an optical disk device, characterized in that for resetting the predetermined flag value to zero.

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